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nonabsdid: Side-by-Side Event-Study Comparison for Heterogeneous DiD

Source: R/nonabsdid-package.R
nonabsdid-package.Rd

The `nonabsdid` package provides a single, consistent interface for running, tidying, and plotting event-study estimates from several heterogeneity-robust difference-in-differences estimators that support non-absorbing (switching on/off) treatments:

Details

  • **DCDH** — de Chaisemartin & D'Haultfoeuille, via `DIDmultiplegtDYN::did_multiplegt_dyn()`.

  • **PanelMatch** — Imai, Kim & Wang, via `PanelMatch::PanelMatch()` / `PanelMatch::PanelEstimate()` with pre-treatment results from `PanelMatch::placebo_test()`.

  • **IFE / Imputation** — Liu, Wang & Xu, via `fect::fect()`.

The user-facing API has three pieces:

  • [nabs_event_study()] runs one of the estimators with a unified argument set and returns its native object plus a tidy tibble.

  • [as_nabs_event_study()] is an S3 generic that coerces native estimator objects into a stable tidy tibble (the *nabs_event_study_tbl* schema).

  • [nabs_event_plot()] takes one or more *nabs_event_study_tbl* objects and overlays them on a single ggplot2 panel, optionally with a naive two-way fixed effects (TWFE) reference series in a neutral color.

Tidy schema

All tidiers return a tibble with class `c("nabs_event_study_tbl", "tbl_df", ...)` and the following columns:

`time`

Integer relative period (0 = treatment onset).

`estimate`

Point estimate.

`std.error`

Standard error (may be `NA` when the estimator only reports CI bounds, e.g. some `fect` configurations).

`conf.low`, `conf.high`

Lower / upper bound of the `conf.level` confidence interval.

`window`

`"pre"` if `time < 0`, otherwise `"post"`.

`method`

Method label, e.g. `"DCDH"`, `"PanelMatch"`, `"IFE"`, or `"TWFE"`.

`outcome`

Outcome variable name (when known), else `NA`.

See also

Useful links:

Author

Maintainer: Takuma Iwasaki iwasakit@stanford.edu (ORCID)

Authors: